(A) Field of the Invention
The present invention relates to a liquid crystal display (LCD) panel apparatus and testing method thereof, and more specifically, to an LCD panel apparatus and testing method thereof for detecting whether any defects exist in common lines.
(B) Description of Related Art
LCDs have many advantages such as thin panel, light weight, low power consumption and low radiation, and therefore have been widely used in current display applications. An LCD display mainly includes an LCD panel and a back light unit. The back light unit serves as illumination source to the LCD panel, and the rotations of the liquid crystals are controlled by electrical signals so as to display images.
The quality of LCD panels significantly impacts the display performance. In order to ensure the quality of the LCD panels, the LCD panels need to be tested, so as to detect whether defects exist.
FIG. 1 shows a pixel array circuit of a known LCD panel. In an LCD panel apparatus 10, scan lines 12 and data lines 13 are interlaced in a transverse direction and a longitudinal direction, respectively, so as to form a pixel array 11 including a plurality of pixel cells 19. Common lines 14 are connected to the plurality of pixel cells 19 in a transverse direction. Each pixel cell 19 includes a pixel electrode 15 and a storage capacitor 16 connected between the common line 14 and the pixel electrode 15. Moreover, a TFT transistor 17 is connected to the corresponding scan line 12, the pixel electrode 15 and data line 13.
When performing the pixel array defect testing, an array common electrode terminal 18 is conductive to the common lines 14 in a two-way manner, i.e., the two ends of each electrode line 14 are connected to the array common electrode terminal 18, so as to receive the signals from the array common electrode terminal 18. Moreover, the common lines 14 are further connected to an IC signal input for receiving common electrode signals during the module stage after testing.
Referring to FIG. 2, the arrow signs indicate current flowing direction when testing the common electrodes. Because array common electrode terminal 18 is conductive to the common lines 14 in a two-way manner, the testing current flows from two ends to the centers of the common lines 14. However, according to this known structure, if the common lines 14 have any open circuit due to defect existence, the open-circuit defect cannot be detected because currents in the common lines 14 flow into the common lines 14 from the two ends thereof. As a result, the panel quality would be seriously impacted.